The primary goal of this research project is to describe secular trends in cardiovascular risk factors in the adolescent and adult U.S. population and to develop and evaluate predictive models involving these secular trends and relevant covariables utilizing data from the National Health and Nutrition Examination Surveys (NHES I, NHANES I, NHANES II). A parallel goal is to modify and implement the statistical methodology available for the analysis of complex sample survey data in order to model and test these secular trends across separate nationally representative cross-sectional samples. Considerable progress has been made in both of these goals with particular emphasis on factors associated with secular trends in body mass index for adolescents and young adults and trends in blood pressure for both young and older Americans. This proposal requests support to expand on the originally proposed specific aims and to introduce a major new thrust in the analysis of the National Health and Nutrition Examination Surveys. This new initiative proposes to develop statistical methods for analyzing HES/NHANES data on blood pressure and other cardiovascular risk factors taking account of the increasing proportion of persons in the population under treatment across the time period under investigation. Powerful statistical methods for producing and analyzing multiple imputation data sets will be implemented and investigated using sensitivity analysis methods. Specifically, the aims of this project over the next grant period are to: 1) Expand the investigation of trends in body mass index from the younger adults to the older adult ages 35-74; 2) Describe secular trend in serum lipids for both young and older adults; 3) Develop and evaluate predictive models for blood pressure under alternate assumptions regarding treatment status effects; 4) Develop computing software for implementing the multiple imputation methods and produce public use analysis files for other investigators; 5) Analyze imputed data set to determine effects of imputation adjustments on assessments of secular trends and conduct sensitivity analyses to determine the effects of model assumptions; 6) Expand the scope of the imputation work to include other cardiovascular risk factors; 7) Implement, modify and compare recently developed statistical software for the analysis of complex sample survey data; 8) Provide guidelines in the choice of analytical strategies that characterize secular trends across nationally representative cross- sectional samples; 9) Compare estimated secular trends across nationally representative cross-sectional samples; 9) Compare estimated secular trends from cross-sectional data with longitudinally derived estimators from the NHANES I Follow-up Study (NHEFS).